Here is Ed's latest design on the right.
This is an O2 sensor display for mixture adjustment
and a digital flow meter that interfaces with Tracy's EFI
computer.

BTW both Tracy and Ed use switches to select the primary or
secondary injectors or both. This in conjunction the EGT read out
does wonders when it comes time to trouble shoot injector problems.
Also good for pre flight just like dual ignition.

Bill Freeman and I had a discussion on the advantages
of electronic injectors over mechanical injectors awhile ago and we
decided at the time there appeared to be only one. Easier
starting when warm. Well here is another one.

BTW Tracy's computer has a built in limp home mode if one or more
injectors fail. Correct me guys if I am wrong. I should have
taken notes.

Paul Lamar

You are correct, Paul

    One of the really neat features of Tracy's  Electronic Injection module
is you can (for price of two good DPDT toggle switches) have both a nice
diagnostic feature as well as a "Limp home" mode.  When one injector of a
pair (primary or secondary) fail, the engine runs quite rough and viberates.
It would probably get you home, but your brains may be scrambled by that
time.  However, if you turn both injectors of a pair OFF, the injector time
on the remaining pair doubles (twice the fuel flow) and the engine will run
just fine on either the primary or secondary set of injectors. You can
almost get full power on a either pair, certainly enought to fly you home
with no problem.

If the engine starts running rough and you suspect an injector.  You simply
switch off one pair - say the primary.  If it then runs smooth you know the
problem is with the primary set.  If no change or it runs worse, then flick
the primary set back on and switch off the secondary set. etc.  DON"T switch
both pairs off at the same time or you will become a glider until you get
one or the other switched back on.

If in addition you have a AF meter with an O2 sensor in the front or rear
rotor exhaust then you can narrow down any injector problem even faster.  I
had an injector fail just prior to flying down to Tracy's.  The engine
started bogging down and the EGT on the Rear Rotor dropped 300F indicating
too much fuel - but the question was it the primary or secondary injector
for the rear rotor, well I turned off the primary and the problem cleared up
therefore I knew it was the rear primary injector.

Anyhow, great seeing you and Robin again at the Fly in.  Looking forward to
the next time.

Best Regards

Ed Anderson

 
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